SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '731e1c1de4247c7cdbae4e2652fc910e4a429b2fda32ab541c1ab837f6d5da7a' 
  AND token = '7QZ8e2un9J0IQScyOPF8Vg4YPAL1yfgwDWMyYoW04So=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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