SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68a881c4b3f15f215efbcfbf6a44bd9d773d399a703a75d8257ba4760522bca6' 
  AND token = 'tKcCyW1X0crhdvoCFjqcqdEVNh2w5lnJ3K3qSn/BlFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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