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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e1dcbb8e0d1aa19c5ef2b09a5a5019e8fd0c5867dd0d165d6e43bd40f0608bc1' 
  AND token = 'xRqqQTsuk/zkTH+caT17tzabSue9mPcGqHxaTvknT/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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