SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6b6eb0356481faac9b2334655ca60b773fd225aa023628e1aebe5046078a98a' 
  AND token = 'XNuErv70SpR2YaGUPp8SuwJxzsUKGFi87/laOpC2HM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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