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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbb686f1ac00f5f10a1eea9fe5a840e812c7f7bb845724c3334352ea4d026edc' 
  AND token = 'H4oM8s/+VYHIfO1tVHcZPPAGl2lzeZSSKCv2Td6/v9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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