SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8b66557e3e36decb947512b57744e2a93a234d1de3809ecb58968d0d3f2f9ee6' 
  AND token = 'BcwAPPfXx5dCceGotwZWOAujerBUHAe76uMkWEHCoYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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