SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8bd824b852fa09879f06f6d24e36df624fc2b32832ff40ed8234f62a152b77d' 
  AND token = 'wz3HKbWjfRY5JDdB6jmuHCg0eyrJufwXDXYPcb/ZLYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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