SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c77bfa355dafda63f2ca9e63358d2e94bc8a9aec1ca00dc71f9e59caed870cf' 
  AND token = 'y6whWMwmiBM5yC99j0BCBmLgJRyOL1jXCC/yQw1bpC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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