SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9aa49e60b468470ee6c9ab150a5af34c99a6a0a9317052d4a2e9a178b6e1957' 
  AND token = '/9Cr34ZNLm1NajS1leHjKvR3t4MgX2FR8VMDKpyq7Kc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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