SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f99f4658d6c39d46f3c3a957e6b920e5805ecdef8114df8b138a89a000e88b6' 
  AND token = 'EpVV4g8YVNSD3C0Nf6xxaFj6DGaxJk6WfobFEQXrRLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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