SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39425350e99b734bee0b0774f371bac1ed1bd9755e2dd636a15e62176a60e8a9' 
  AND token = 'b8TSZmzf2mfEfjO23jKmhzDqFWZy6SBlu7iKL7UScwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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