SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b77bfe045835836ffe38fab3107c2baca92b6bcd795565b7c7fa3203818d2c2d' 
  AND token = '5F2fGt2VtZEktrK14SFhtvWMq5ctHSQ3P5gAiJhWgmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}