SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61c9ece566d5931adf2b47fa8575d98f2c3c2f8c7cd2106347213e25c79725ea' 
  AND token = 'MhYZfgwEziXtVZ6lvFeYTZobZIsDwM0hQlAgGDdmqHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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