SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3ac00febdecd987c507801317cd7c676b2d09f0bf9813e3876fd98b576148e9' 
  AND token = 'H+P9yRiixBFy4J16rhP9gTQhGYrF6LCJpPQyn1j/cZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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