SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c428ed5cf31e03e9e42f46ea64a47e3892990baaa7740b686da0ea9969eb77c' 
  AND token = 'h1muEmjpOPG+tgO1RRsulGL1lwlYmIR2BOimxp+2wBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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