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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e1cf549ae95c626462048258e2b6d4df6bd9b35ccdfe4d8dd9d590d02e998931' 
  AND token = 'vnmeQUN2ZtgfQDooVPWq0HgqYQq4Do0Sj5hElm5Al9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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