SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdfb9e991685f64765ef2e4435b7771e67850abd28d4918e9cd86bb5c090d01b' 
  AND token = 'DOLXqwMjWrE1iJNlZGhbN4fSE8xxFLbmuNTXxDfNEIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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