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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c5537cec36cb78762fe8383e1a1dcf0e7ada165a6d4819eef864963588f610ed' 
  AND token = 'WEX4ckjPSzPhUEPNN+0rMsGCl8veE5Iu3utqlgfVWOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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