SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6eb76a2982c0d74251b69075383780fce0af2da9b7de60613595a851f95508dd' 
  AND token = 'Zk+EEl9qjKg/CpEIk13QmrE3E/Kit4iKJcUBrrUp6Ic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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