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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4fd64ed661a8f4c06f3e2219c7e1ef9d3a111d9ded809faa2b8eaea66a0c6e9d' 
  AND token = 'lJWFg2YQaLWY4rg4QeTZMokIbmxLBlPbmjArgMMLtCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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