SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac4540e34c62e38492982116ee6fc746ce13345d4c5d0d9482a7144c5cffc947' 
  AND token = 'AqUBAuvjzXlfurEhw6BmWHJJxr66gQGkgpIR+MxBjMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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