SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92d61349b7ae08451322dedb53ab16936a981e3d2bfa72718784f6137d6b3def' 
  AND token = 'MgM//KsvImRVX/lRqzRh8104vYwx3rli3HS+cxHCr4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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