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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c319ebbbe65ac83cf143da54e8216219d9131c037df2dcea2a694df520ceb2b6' 
  AND token = 'MT3Mo0GhYAkTidFTsEPgljg7rN0ki9SBr/7UX+EIUuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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