SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a37bfe13b3fb667e0052949f626fbf5edc3cdd5352781b73706ae3e6989325f0' 
  AND token = 'SRzdQowLYHDp8StHOMHRgGE8VRXtcZEeocnXKE995Zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}