SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '321d41d8142a746b731193ab201c7552f71cedc24ee4b90d8243888db2a5adef' 
  AND token = 'HrhSrk9APm1oA3Zf4WWdUPMiNx3TPWw4iuHZwwRvsow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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