SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '973123b2cfdf185fec282234c77b0738c1b33d544b79af0626afb474d2ecccad' 
  AND token = 'IAm+X9XOwbRtszih5zDRq0rj/U7/zz5ifPG/vCKl3zs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}