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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1bc0b004cdbb67214ad5f188e28064c213ec4bf4b9f8be60d7aed73b3ae877a' 
  AND token = 'AKuoBKHL01uhr+gsF7/NcgAJF9G7tAc+pbHO55OoFYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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