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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '993c3b09d83a7fe024b009dcba8ac938d5fcf9fcde2d3894a7d13b966af3bf1f' 
  AND token = 'n2dme+E7orA31/vDNiQAyEP2d5uYkqOpkNUwuC07I1w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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