SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30cea73485485dd0b2515041d3e960c6535fc57df4455c2887e136ff31b0b045' 
  AND token = 'YkYkeO2x8HCphQIoSQs1Avq8OBVEOzMxGfsDpW4recE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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