SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd882758a44d71acd76bcdbe37603472be3aeee4f539b42841c048139f0b25b48' 
  AND token = 'ueyfYriyIA031MFJkXB/OiyubIFJzvLf4rh10FmkVcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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