SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6fcfbed78671ddcc652ba77709b02976d191dac66c74e28bc9233dc082196632' 
  AND token = 'Kou1iUyVWOFwoJAgjlgH2dWHahyWbkuUxChL4TiyqLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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