SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50141a7e6e5170f3aca9f36910daf98edc666c19c0e20ac4e7b8ee85fb4ef88f' 
  AND token = '1a8fRJhOXJonJwYgXUu/KBsYAapbwUb6+7yvR82Fssc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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