SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41ec328bb866616eed859e24461be776824e4f24adc78b5efaa8990479fcc828' 
  AND token = '0cY897LRsz1v5W2LVBABhHxjJMPPicmajUKH2anEs5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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