SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3c858cf3628a355a56f17de23a7110c7a765f0ccbb1b525761cb004a3d22525' 
  AND token = 'CdfuHdfys3Y7w8PGbxBQKpJBXJMNRnqk1JzEW8YFdKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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