SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c2a814ad86559e2b5f0083a6684245d209017e123ddffdf13972def3bd6949b' 
  AND token = 'M2jgVgZwp8sph1/RiZLKpJ6u/IN8Vd6O0vL8W7THUCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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