SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4564dc296ecc51558bc9fac1a24070848e25981f8f48d8c0b584854dfb58175' 
  AND token = 'uiSTDJ+zsTOYeSL5QrKoy98A4OqpoEI5K1c66U5y3No=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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