SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9527bef386882854bb4a7b0e661ff79b04b2d33f1494acbc592778eccf722090' 
  AND token = 'zrIGcR6vKhJ8DgZ7xl4aHBCOJYqGQxocw570szZ+fHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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