SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2b063c963f456a60ec6f80ef0bf70e250bb6c1491da14f0e62ba97dee7dcbc1' 
  AND token = 'MGCERzyeEHysAf0QJ2SyJdpnkD39zgxMd7O7JgE/PbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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