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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '623fcdb6ba8fc434b06791c816d86e4139fa2d54043e70ff9c9a32533aed3c48' 
  AND token = 'rpw9AtO7BVsdwo28uMsMwSQ1hQ3/V2usf0pz3ytTRv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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