SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5976a93b1048e4760ed523d046af7400eb0e97cc451b063ff15b3aba51b845c' 
  AND token = 'obupclxalKO8yJ52FhMEcqtY/KNfrYltVBFHblTyuuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}