SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e08eabfc0da00a452d58040e730cf238a5b50f55e3ebf51a111d2f0b3b27e3e8' 
  AND token = '7r7HKtBP81O1dsuiZIAWkvaaqcT9Vyq4+i+dETPeZSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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