SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9aa398053c0a308edf0e008237b0d3285e6a212d506e5ccde8865ec1b65ec2b' 
  AND token = 'OutDLljpThexC/BpbgvS12w05vFKnYMaAp14Ln+WDEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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