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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a6d7c80f39fd2c345d61e9b3c9fd2d41e0233f0cf4b0ef74364acd9724918301' 
  AND token = '447fKh4zbd55eZYDpMylnqwEvDhkzeKFM35aB//ajC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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