SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9ab1cce9eb3e725b9b4e9ba111c0dbdfc5655801ac49182bbf257e09dbdf845' 
  AND token = 'EEbUmN1DGh6+4jYYQyPfPLOOAeDqdyLRuDkt7EgvkTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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