SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f81660fa703f91af4a1caf5a715c79975ad3fd22492b533f9e7c14ef66e6b4bd' 
  AND token = 'd5wEHFFKPlFCxQva29c9VBICc19YJFK+8qAu/Z16EqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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