SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b3e9beaad9afaa26e3afecec95fef36ff95a1445847787cadc270d376536a36' 
  AND token = 'HNEabWsWRjAaC/skHcQh5XbSeoVpPgB/q5JIajt78xc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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