SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b590ef66a9055e22213e61fce265574993e012d2578039b74b7f3fc06952288' 
  AND token = 'JhftKWk0GFQjZvoThI6zBezZ840gJnzNcV23qll71aY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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