SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b13656de68b83bd1872667e9909cfef84f81494073878a634365d3137087a15e' 
  AND token = 'vePqJU40ZXqA3igZNGVrAqDVeC+RN1c3+NgA7bWUATw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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