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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3683c58aec80e65e57bb5654f2785d1c9824dfecc46e3a22a07f16843f0198a5' 
  AND token = 'cgXJy5v/LfQ1lVdYf2PAkpdDQ0cA3T1W8mgcOn3PT4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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