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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6add3a0eb1eac780cd182deaef367d031b72ec9edea3270bb7c6822150d6d09' 
  AND token = 'j1ObBfeUhmWwqy6Ej7SBXQfxQ+0Ew937/rc+2VGxL6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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