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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6ea8470386cc3a5837a4b888cceac51d72d17aaaec075fad5c3835c9d4a6c1a2' 
  AND token = 'ddLk2KxI68D0WY3IsgqSHo1r+09lzeLxtbmwggurgYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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