SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b657c88b88ff4002938aeead1c8d1378c53f01a35b5700675c8b8213a59bed1b' 
  AND token = 'B8nT8dvdkLyK2Fv1o/EiNvbdTduAYoPGI2XJIHmIc6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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