SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b55bd262c77915f154851fb362679deab3fc2105682f5fd035cd794bb5911d1' 
  AND token = 'utQGxUebixkr3p6A/J3mNvf0uTc8GBqGMhBFwhfy9rg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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