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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '87217c78107b6bd35a5ce9ec793e91d981f1648ff039355b174932ef876b86b3' 
  AND token = 'x3aZqgbTA5+Pi5fUH652iztwcgT3gxw2EDIlIsqpMrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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