SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f96472fe89fbdbfa797c56b2c921ce831b3a0cda83d12b0e96c2de702b19358b' 
  AND token = 'uYh4UT/wPGOjMrQFBSkVj4RgkzsvYfzpVv4zs2Yv9tk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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