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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '20a236c02ce546c0d978541c3d58fcaff6fca0cc6d9ae044ebe7fc3e8e0395b8' 
  AND token = 'q/Hb4d2L/8IQaSXtNviBTeKYJ7ZVeENeS/FxwlNfLEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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