SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fd8f7db5287c0ad699fa75b2c080af232e3b2d7497061c9b47f6f1eb6222a97' 
  AND token = 'mXT/ISh/bmtl6TzGM3bIZgmebKvGv6gUgQKYtmcDnR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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