SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17a9ee4f29303fef763fe8677af526f3409c75ddd1da9bb8cc7aff8f0bb1e972' 
  AND token = '4AMT3rl7qM2hSYZ+lPiAW7bu+n6ZLMnuFBwKvlhSUPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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