SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '785a6094bf4cd80335504f778b7e04c9882054259a51eb04b99f3defee031a65' 
  AND token = 'YoB0yzP67H67X9NOMgBpC2b3wgn6dtfmVoUPdL+gTyw=' 
  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"
    }
  }
}