SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0f96878cd4278dc32b95f80236c68bde116f99eddb064597ed40b09aaa37747' 
  AND token = 'EjlRvhqPiT7iJQvWGSTP+s0gzNJ++hhYMWKL1Rnpgow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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