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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef8c970b3d7334b67e7a708464b5efe460ffe2fff77a55a2ce08cef4adc8649d' 
  AND token = 'Srd0NjPbyR4AnN6G6DTB2rBpXIZ2IafcFYNBDgr5CVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}