SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1f9dc2e38be07d78439aefa0ba4c665c179f99c79a52d1bd1f9f78231ec95800' 
  AND token = '2WG/JqhwP7Uxna2duDow+5mKWOPglQpVrDdtTPPGxI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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