SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '252cc2828579d5c189920b388b4912880a96c74b6ff7da4507d41e1dfab87f38' 
  AND token = 'viOoi4r72jvUV27ouAWwaBxQPzRJdMDQCJQCo76ZdPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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