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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ab77551f00a12b0e8554e81f2f03b2dd4e3b12535f6a9f9f69add85e091e3d9c' 
  AND token = 'Wmt3lhoHs7AxAlR9a7esMic57M39jZCbTby/cnlHe/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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