SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b88422075426559db6fcede7e1d1a305eaa213415b4eefd913547d94d7ece604' 
  AND token = 'In/lOICQ0vsXcCO6RlWMpRrpP4D4O1Hf0Q/r9HdCkUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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