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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77a066e7d925ceea80809944f6fffe1a748b79a7e9d015ec987bc8ee321b0ad5' 
  AND token = 'OqXNk5+krejtGUh3L54vYffBJpUmwLqSDPJnu4RGIn4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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