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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd3d23b2b42bf756b1d1d13eb91ea34b2e08ef1b4177795fd395e90ba4dd63f0e' 
  AND token = 'ywbZYwQPfkb1+kRbxhUMBtcdmr/nh2RlrNQtnMofzkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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