SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe020b57ba9c097972aeec95b91613b6d896640ec10b8ca3d32ad5f8edb9ebf5' 
  AND token = 'Ge8+wPdT1/cxZjZYjv3GiEG6rkVCPuMFm+2poCTqhuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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