SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb1cf26e397dc3763da3224bec804f9328eae71f5da1ebc65cedaede54c4acd3' 
  AND token = 'HhymqDXNKYJrNRPHND+gFkECYxYsHF4AVBYY850rIXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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