SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56b579b68fc88b48ab5ffa164fcceb0a7062bda204f9a74beb82601a2c603cbf' 
  AND token = 'qgYL32sjEe/mkVRidFHkQAAjgj6b2icVjPgI6BD1vZg=' 
  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"
    }
  }
}