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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9adf2e116f6f503eabf3d5de69312c2139e61bc99513c17ecd37da56a1a11ee' 
  AND token = 'MQCf2fzfsxkoTuYevLoDBnnsB/Tk84Vo2vaqDs0ewUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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