SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd673edf757add70f7eea480c1e3233aef386147ecdfcad89310d66d916e3e8e2' 
  AND token = '7lI8vupc8VHJKH7VPFizaYzPavzmo/GXsX9osjdmufM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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