SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '104cc21a79628b6a2609b64d9e9bfd9b0ea5ab5ef8c59bde47f0d3d89e43d850' 
  AND token = 'tFhRKGdmcB/V/m2vQcbVLyP0CoLQOa5IMFdJP55dHNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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