SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8122beea7750a6f486cbef84163d4eeaf7c58c9b44ecc5d2c9cca0aac3737b10' 
  AND token = 'JQD98IQWyUEYH3PQp6bUsajnItaGHWDMbdzkJGT1Vqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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