SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f2334f2d80f61a89ee2f76d172353c5a094c2d1e5366eb47ad92062bd44538d' 
  AND token = 'PUw9mT3kup3nkO5/Rz8j+K21ETuwaAXdQyV/hYjQEss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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