SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20e705a56a7ca51b848a8da63898371c929fc3f2e2284c02cbb8576ae0e65c46' 
  AND token = 'f6m7iYTFvyQHI5Subf0DV6A55ISGnJYT79tejK7yUfk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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