SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59416c6dc40c85cd43bdc0a3eba870d80160be636a885ccaa91ee58069c47677' 
  AND token = 'iMk8YEnAfHFWlYoeRbH3mHVkVtvXmzUThfNdHbKudek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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