SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a924d6e5b8453aac19135d28053df595344068e2ca193c43f0a90fbc903952dd' 
  AND token = '8AudMUn2WtrIBeVHExVQ8zZArvWtL4ZuEwORu9Tv0hE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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