SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a0fd1f67974bb660321427d39377ce27cf55b95bd451ef26c1443917e0f1d23' 
  AND token = 'sPUN2s2aqC57PQZNSvCrPBunAPTXiQlGL+PPyVPgpQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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